Cancer is a term used to describe a group of malignancies that all share the common trait of developing when cells in a part of the body begin to grow out of control. Most cancers form as tumors, but can also manifest in the blood and circulate through other tissues where they grow. Cancer malignancies are most commonly treated with a combination of surgery, chemotherapy, and/or radiation therapy. The type of treatment used to treat a specific cancer depends upon several factors including the type of cancer malignancy and the stage during which it was diagnosed.
Taxol, also known as paclitaxel, is one of the more common cytotoxic agents used for the treatment of Breast (Holmes et. al. Proc. Am. Soc. Clin. Oncol., 10, 60, 1991), Ovarian (Einzig et. al. Proc. Am. Assoc. Cancer Res., 31, 1114, 1990) and non-small cell lung cancer. Taxol has the formula:

This compound has been associated with debilitating side effects such as bone marrow density loss, allergic reaction, neutropenia, hypotension, bardycardia, nausea and vomiting. By monitoring the levels of taxol in the body and adjusting the dose these side effects can be better controlled and limited in patients.
At the same time, there is often highly variable relationship between the dose of taxol and the resulting serum drug concentration that affects therapeutic effect. The degree of intra- and inter-individual pharmacokinetic variability of taxol can be as high as 5-fold (Gurney et. al., J. Clin. Oncol. 14, pp 2590–2611, 1996) and is impacted by many factors, including:                Organ function        Genetic regulation        Disease state        Age        Drug-drug interaction        Time of drug ingestion,        Mode of drug administration, and        Technique-related administration.        
As a result of this variability, equal doses of the same drug in different individuals can result in dramatically different clinical outcomes (Hon et. al. Clinical Chemistry 44, pp 388–400, 1998). The effectiveness of the same taxol dosage varies significantly based upon individual drug clearance and the ultimate serum drug concentration in the patient. Therapeutic drug management would provide the clinician with insight on patient variation in both oral and intravenous drug administration. With therapeutic drug management, drug dosages could be individualized to the patient, and the chances of effectively treating the cancer, without the unwanted side effects, would be much higher.
In addition, therapeutic drug management of taxol would serve as an excellent tool to ensure compliance in administering chemotherapy with the actual prescribed dosage and achievement of the effective serum concentration levels. It has been found that variability in serum concentration is not only due to physiological factors, but can also result from variation in administration technique.
Routine therapeutic drug management of taxol would require the availability of simple automated tests adaptable to general laboratory equipment. Tests that best fit these criteria are immunoassays. A radioimmunoassay and an enzyme-linked immunosorbent assay) ELISA assay have been reported for taxol (Erlanger et. al. U.S. Pat. No. 5,756,301, May 26, 1998). However the derivatives and immunogens used in this assay impart to the corresponding antibodies a broad cross-reactivity to taxol, and taxol metabolites, particularly, 6-α-hydroxypaclitaxel. In order to be most effective in monitoring drug levels the antibody should be most specific to the active compound and display very low cross-reactivity to no cross-reactivity to the non-active metabolites.